1. Field of the Invention
The present invention relates to an image forming system, an image forming apparatus and an image forming method that support a so-called pull print function and, more specifically, to a technique for lessening machine dependency of print data.
2. Description of the Related Art
Conventionally, in a configuration for forming an image (typically, printing an image on paper medium) of a document or the like, generated by an information processing apparatus such as a personal computer, by an image forming apparatus such as a printer, the information processing apparatus and the image forming apparatus are connected to each other through a network and print data is directly transmitted from the information processing apparatus to the image forming apparatus. In such a configuration, the information processing apparatus and the image forming apparatus are connected in one-to-one correspondence.
As another approach, a so-called client-server type configuration is also available. In the client-server configuration, print data transmitted from a plurality of information processing apparatuses are once collected to a server, generally referred to as a print server. The print data (or print jobs) collected by the print server are transmitted to the image forming apparatus in a prescribed order. In this configuration, a plurality of information processing apparatuses share one image forming apparatus, by the server.
Recently, a scheme referred to as “pull print” or “ubiquitous print” has been proposed, which is an improvement over the client-server configuration. In the pull print supporting configuration, a server collects print data generated by any of the information processing apparatuses, and any of the image forming apparatuses selectively obtains print data collected in the server and forms an image of obtained print data. As an example of such pull print supporting configuration, Japanese Laid-Open Patent Publication No. 2004-220354 discloses a network printing system that allows a user to directly and plainly specify an output destination printer. The network printing system includes one or a plurality of client terminals, a print server and one or a plurality of printers, connected by a network.
In such a pull print supporting configuration, it is possible to form an image of an arbitrary print data by an arbitrary image forming apparatus. Therefore, when an image forming apparatus is busy with processing, destination can easily be changed to another image processing apparatus to finish the process.
Image forming apparatuses of late allow installation of various and many functions, and by such functions, various print settings may be made when the print data is generated by the information processing apparatus. The print setting designated on the side of information processing apparatus is added as setting information to the print data and transmitted to the server.
On the other hand, among the plurality of image forming apparatuses, there may be one not supporting most of the above-described functions. Therefore, when print data, prepared on the assumption that various and many functions are available, were processed by an image forming apparatus having limited functions only, the resulting output would be unsatisfactory. If the output destination of the print data is limited to only the image forming apparatus or apparatuses fully equipped with the necessary functions, the advantage of pull print type configuration that the print data can be processed by any of the image forming apparatuses cannot fully be enjoyed.
In this connection, assume that an image forming apparatus is equipped with most of the functions except for some functions of relatively low priority. The resulting output from such an image forming apparatus may be satisfactory to some users. In the prior art pull print type configuration, however, it has been impossible for the user to know in advance to which extent the print data request can be satisfied by each image forming apparatus. Therefore, it has been difficult for the user to easily determine which image forming apparatus is to be used for processing the print data.